Contact

Email [email protected].

Useful things to include:

• For a correction: the calculator, the numbers you entered (the "Copy link to these results" button captures them all) and what you expected to see.
• For a new calculator idea: what you were trying to work out and what you had to measure.

We read everything but can't give project-specific engineering or code advice. For that, your local building department or a licensed contractor is the right call.